An inkjet printer as an example of a liquid droplet ejecting apparatus includes: an ink cartridge (liquid storage container) mounted on a main body frame; a carriage configured to reciprocate in one direction; an inkjet head (a droplet ejecting head) which is mounted on the carriage to eject droplets from a plurality of nozzles; a sub-tank (liquid tank) mounted on the carriage and connected to the ink cartridge via flexible tube. This inkjet printer prints desired images and the like by ejecting inks onto a recording medium from the plurality of nozzles of the inkjet head while the carriage reciprocates.
In the inkjet printer, when the carriage changes its moving direction, inertial force is applied to the ink in the tube connected to the sub-tank mounted on the carriage. Then, due to inertial force applied to the ink in the tube, the ink flow into the sub-tank from the tube, or the ink flow out of the sub-tank into the tube. Due to dynamic pressures of the ink, an internal pressure in the sub-tank fluctuates, and a back-pressure of the inkjet head further fluctuates, which results in an effect on the ejection characteristics from the nozzles.
JP-A-2005-271546 describes an inkjet printer for reducing such pressure fluctuation in a sub-tank. The inkjet printer includes a sub-tank to which a damper unit is provided. The damper unit has a flexible film for damper at a position facing inflow an opening into which an ink supplied from a tube is made to flow. This inkjet printer absorbs a dynamic pressure of the ink generated in the tube with the flexible films when the carriage changes its moving direction.
However, if a recording speed becomes high, it is difficult for the flexible film in JP-A-2005-271546 to sufficiently absorb the dynamic pressure of the ink generated in the tube since the dynamic pressure of the ink generated in the tube when the carriage changes its moving direction becomes high. That is, when an attempt is made to sufficiently absorb the dynamic pressure of the ink generated in the tube, a flexible film having extremely large area is required, and the sub-tank and the carriage on which the sub-tanks are mounted would become greater.